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Chapter 53 Notes
Community Ecology
What is a Community?
A __________ is any assemblage of
populations in an area or habitat.
Communities differ dramatically in their
species richness and relative abundance.
- _______________: number of
species contained
- ____________________: number of
different species
What is a Community?
________________: a community is a
chance assemblage of species found in
the same area because they have
similar abiotic requirements.
___________________: assemblage
of closely linked species, locked into
association by biotic interactions.
What is a Community?
Interspecific Interactions
and Community Structure
____________________: interactions
belonging between populations of
different species under one community
Competition
___________________ for resources
can occur when resources are in short
supply
Interspecific Interactions
and Community Structure
Interspecific Interactions
and Community Structure
___________________________:
- two species are so similar that they
compete for the same limiting resources
- one will use the resources more
efficiently and reproduce more
- this will lead to local elimination of the
competitor
Interspecific Interactions
and Community Structure
Interspecific Interactions
and Community Structure
________________
- sum total of a species’ use of biotic
and abiotic resources in its environment
- how a species “fits into” an ecosystem
- where it is and what it does
Interspecific Interactions
and Community Structure
______________________:
- if a species will evolve to use a
different set of resources
- leads to a differentiation of niches
Interspecific Interactions
and Community Structure
Predation
- includes the killing of one animal by
another, herbivory, and parasitism
- predator adaptations
- plant defenses against herbivores
- animal defenses against predators
Interspecific Interactions
and Community Structure
Interspecific Interactions
and Community Structure
- __________
____________:
animals with
effective chemical
defenses are
brightly colored to
act as a warning
Interspecific Interactions
and Community Structure
- __________
___________:
a species of prey
will gain
protection
through mimicry
Interspecific Interactions
and Community Structure
___________ is the symbiotic
interaction in which the parasite
derives its nourishment from the host
- ______________: interaction
that benefits only one of the species
involved in the interaction
Interspecific Interactions
and Community Structure
- ___________:
interspecific
interaction that
benefits both
species
Interspecific Interactions
and Community Structure
Trophic structure is a key factor in
community dynamics
_______________: feeding
relationship between organisms
- food chains
- food webs
- trophic levels: links in the food chain
Interspecific Interactions
and Community Structure
Interspecific Interactions
and Community Structure
Food chains are limited to four or five
links
- ___________________: only 10%
of the energy stored in organic matter
is converted to the next trophic level
Interspecific Interactions
and Community Structure
Dominant species and keystone species
exert strong controls on community
structure
________________: species that have
the highest abundance or biomass
________________: species that exert
strong control on community structure
by the ecological niches
Disturbance and community
structure
Communities follow an nonequilibrium
model: they are seen as constantly
changing after being rattled by
disturbances
- storms, fire, human events, etc.
Disturbance and community
structure
Ecological succession is the sequence of
community changes after a disturbance
______________ succession:
transitions of species composition over
ecological time
___________ succession: begins in a
lifeless area such as a new volcanic
island
Disturbance and community
structure
_____________ succession: occurs
when an existing community has been
cleared by a disturbance that leaves the
soil intact
- early arrivals may facilitate, inhibit, or
tolerate later arriving species
Biogeographic factors
affecting biodiversity
Two key factors correlated with a
communities biodiversity are its
_____ and _____________________
- small or remote islands have fewer
species than large islands or those near
continents